An ink jet printer is as an example of a printing apparatus that ejects droplets of ink onto a recording medium such as a sheet of paper for printing an image of the recording medium. Ink jet printers include one or more print engines having at least one ink jet print head provided with an ink cartridge that accommodates the ink. In operation of the print engine, ink is supplied from the ink cartridge to ejection nozzles in each print head so that a printing operation is performed by ejection of the ink droplets from selected ejection nozzles.
Periodically during printing an ink jet print head is required to be flushed to ensure that the individual jet nozzles stay wet in order to prevent defective jet conditions attributed to ink drying at unused nozzles. One commonly implemented flush method is referred to as “line flushing.” In line flushing all primary colors are printed on top of each other in straight line across the top or bottom of each printed page. Another flushing technique is referred to as “random flushing”, in which drops are frequently ejected from each nozzle during print production.
However, nozzles may continue to become clogged using these flushing techniques because the frequency, or volume, of ink to be ejected from the nozzles may need to be increased during print production in order to prevent nozzle drying. Currently, no process is available to adjust nozzle flushing frequency during print production without stopping the printer.
Consequently, what is a needed is a mechanism to dynamically adjust nozzle flushing frequency during print production.